Total synthesis and structure revision of chrysamide B

Abstract

Total synthesis of the originally proposed chrysamide B (2) is described, which features a convergent assembly of the chiral piperazine core and epoxy-acid. Mismatched spectroscopic data for the synthetic sample compared to that for the isolate led us to propose the revised structure 3 based on biosynthetic considerations. In a further antibacterial assay, chrysamide B and its diastereomer 2 exhibited different activities.